Impact of early aggressive nutrition on retinal development in premature infants

Influence of gastric residual assessment in preterm neonates on time to achieve enteral feeding (the GRASS trial)-Multi-centre, assessor-blinded randomised clinical trial

PURPOSE

Gastric residual measurement is routinely performed in premature infants prior to feeding despite a lack of evidence of benefit. We aimed to evaluate if the exclusion of routine gastric residual measurement and evaluation has an impact on the time taken to achieve full enteral feeding in preterm neonates.

METHODS

International multi-centre randomised controlled trial. Clinically stable, appropriate for gestational age infants between 26+0 and 30+6 weeks of gestation and less than 1.5 kg birth weight were eligible. Infants were randomised to the intervention arm (no monitoring of gastric aspirates) or control arm (routine care). Primary outcome was the achievement of enteral feeds of 100 ml/kg/day by day 5 of life.

RESULTS

Ninety-five infants were recruited with 88 included in an intention-to-treat analysis, 45 in the intervention arm and 43 in the control arm. There was no imbalance in baseline characteristics. Thirty-three (73.3%) infants in the intervention group and 32 infants (74.4%) in the control group reached full feeds by day 5 of life (p = 0.91) with no difference in median time to full feeds. There were no statistically significant differences in survival or the major morbidities of prematurity.

CONCLUSION

 There was no difference in time to attainment of enteral feeds of 100 ml/kg/day in premature infants when gastric residuals were not monitored. In the absence of a clinical benefit to routine monitoring, it may be appropriate to discontinue this practice and only monitor residuals when clinical concern of feeding intolerance or gastrointestinal pathology arises in this group of patients.

TRIAL REGISTRATION

 NCT03111329- https://clinicaltrials.gov/ . Registered 06/04/2017.

WHAT IS KNOWN

• Previous randomized trials have shown little benefit to the performance of routine assessment of gastric residuals in preterm infants. Despite this, they continue to be performed due to concerns from observational data regarding development of NEC. Meta-analysis to date has failed to answer the question regarding NEC.

WHAT IS NEW

• In very low birth weight infants who are fed using modern feeding practice of faster feed advancement, to minimize use of central access and parenteral nutrition, exclusion of routine checks of gastric residuals did not increase the proportion of infants reaching full enteral feeds by day 5. No harm was seen when residual checks were not performed. • In the absence of a clinical benefit to the routine performance of gastric residuals in very low birth weight infants, it may be appropriate to discontinue their use and instead check residuals when clinical concern of pathology arises.

The Effects of Early Enteral and Parental Nutrition on Retinopathy of Prematurity: A Systematic Review

The management of preterm newborns must consider the severe problem of retinopathy of prematurity (ROP). A systematic review has been conducted to effectively acknowledge how enteral and parenteral early nutrition affect the growth and progression of ROP. The study summarizes recent findings from various sources to give insight into the relationship between dietary practices and ROP risks. When untreated, retinopathy of prematurity (ROP) may cause severe vision loss or blindness in premature newborns. The latter two phases of ROP progression are the most serious. A child's early nutrition, both orally and intravenously, significantly impacts the severity and progression of ROP. This systematic review aims to examine the evidence linking early nutrition to ROP in premature infants. The study used Embase, Scopus, and PubMed to conduct our search. ROP, premature newborns, and nutrition were keywords used to find relevant papers. Nine research studies made it through the screening process and offered important information on the impact of diet on ROP. These studies support the idea that poor nutrition is a driving force behind the onset of ROP. The risk of ROP has been associated with postnatal development, hyperglycemia, polyunsaturated fatty acid levels, and the presence of breast milk. The outlook for ROP has also been discovered to be affected by the length of time the patient has received parenteral feeding. The incidence and severity of ROP may be mitigated by providing better nutrition to premature newborns. This comprehensive study concludes that early nutrition, both enteral and parenteral, substantially influences the development and progression of ROP in premature newborns. The significance of nutrition in newborn care is highlighted by the possibility that improved dietary methods might aid in preventing and treating this vision-threatening illness.

Complete blood count parameters as biomarkers of retinopathy of prematurity: a Portuguese multicenter study

PURPOSE

To evaluate complete blood count (CBC) parameters in the first week of life as predictive biomarkers for the development of retinopathy of prematurity (ROP).

METHODS

Multicenter, prospective, observational study of a cohort of preterm infants born with gestational age (GA) < 32 weeks or birth weight < 1500 g in eight Portuguese neonatal intensive care units. All demographic, clinical, and laboratory data from the first week of life were collected. Univariate logistic regression was used to assess risk factors for ROP and then multivariate regression was performed.

RESULTS

A total of 455 infants were included in the study. The median GA was 29.6 weeks, and the median birth weight was 1295 g. One hundred and seventy-two infants (37.8%) developed ROP. Median values of erythrocytes (p < 0.001), hemoglobin (p < 0.001), hematocrit (p < 0.001), mean corpuscular hemoglobin concentration (p < 0.001), lymphocytes (p = 0.035), and platelets (p = 0.003) of the group of infants diagnosed with ROP any stage were lower than those without ROP. Mean corpuscular volume (MCV) (p = 0.044), red blood cell distribution width (RDW) (p < 0.001), erythroblasts (p < 0.001), neutrophils (p = 0.030), neutrophils-lymphocytes ratio (p = 0.028), and basophils (p = 0.003) were higher in the ROP group. Higher values of MCV, erythroblasts, and basophils remained significantly associated with ROP after multivariate regression.

CONCLUSION

In our cohort, the increase in erythroblasts, MCV, and basophils in the first week of life was significantly and independently associated with the development of ROP. These CBC parameters may be early predictive biomarkers for ROP.

Retinopathy of prematurity: A review of pathophysiology and signaling pathways

Retinopathy of prematurity (ROP) is a vasoproliferative disorder of the retina and a leading cause of visual impairment and childhood blindness worldwide. The disease is characterized by an early stage of retinal microvascular degeneration, followed by neovascularization that can lead to subsequent retinal detachment and permanent visual loss. Several factors play a key role during the different pathological stages of the disease. Oxidative and nitrosative stress and inflammatory processes are important contributors to the early stage of ROP. Nitric oxide synthase and arginase play important roles in ischemia/reperfusion-induced neurovascular degeneration. Destructive neovascularization is driven by mediators of the hypoxia-inducible factor pathway, such as vascular endothelial growth factor and metabolic factors (succinate). The extracellular matrix is involved in hypoxia-induced retinal neovascularization. Vasorepulsive molecules (semaphorin 3A) intervene preventing the revascularization of the avascular zone. This review focuses on current concepts about signaling pathways and their mediators, involved in the pathogenesis of ROP, highlighting new potentially preventive and therapeutic modalities. A better understanding of the intricate molecular mechanisms underlying the pathogenesis of ROP should allow the development of more effective and targeted therapeutic agents to reduce aberrant vasoproliferation and facilitate physiological retinal vascular development.

Role of Hormones During Gestation and Early Development: Pathways Involved in Developmental Programming

Accumulating evidence suggests that an altered maternal milieu and environmental insults during the intrauterine and perinatal periods of life affect the developing organism, leading to detrimental long-term outcomes and often to adult pathologies through programming effects. Hormones, together with growth factors, play critical roles in the regulation of maternal-fetal and maternal-neonate interfaces, and alterations in any of them may lead to programming effects on the developing organism. In this chapter, we will review the role of sex steroids, thyroid hormones, and insulin-like growth factors, as crucial factors involved in physiological processes during pregnancy and lactation, and their role in developmental programming effects during fetal and early neonatal life. Also, we will consider epidemiological evidence and data from animal models of altered maternal hormonal environments and focus on the role of different tissues in the establishment of maternal and fetus/infant interaction. Finally, we will identify unresolved questions and discuss potential future research directions.

IGF-1 Promotes Epithelial-Mesenchymal Transition of Lens Epithelial Cells That Is Conferred by miR-3666 Loss

The abnormal proliferation, migration, and epithelial-mesenchymal transformation (EMT) of lens epithelial cells (LECs) are the main reasons for vision loss caused by posterior capsular opacification (PCO) after cataract surgery. Insulin-like growth factor-1 (IGF-1) was found to be associated with the pathogenesis of cataracts, but its biological role in PCO is poorly understood. In the present study, IGF-1 overexpression facilitated the proliferation, migration, and EMT, whereas knockdown of IGF-1 markedly suppressed the proliferation, migration, and TGF-β2-induced EMT of LECs. Additionally, to evaluate valuable microRNAs (miRNAs) which target IGF-1 to modulate LEC-EMT, we predicted miR-3666 might regulate IGF-1 by binding its 3'UTR according to the bioinformatics database. Furthermore, we verified that miR-3666 directly targeted IGF-1 by luciferase reporter assay. By using miR-3666 mimics, cell proliferation, migration, and invasion were suppressed, while being enhanced by the reduction of miR-3666. Knockout of IGF1 reverses the effect of the miR-3666 inhibitor on the malignant behavior of LECs. These results indicate the role of miR-3666/IGF-1 in LEC-EMT that offers new strategies for the therapy and prevention of PCO.

Retinopathy of prematurity: contribution of inflammatory and genetic factors

Retinopathy of prematurity (ROP) is a retinal vasoproliferative disorder that represents an important cause of childhood visual impairment and blindness. Although oxidative stress has long been implicated in ROP etiology, other prenatal and perinatal factors are also involved. This review focuses on current research involving inflammation and genetic factors in the pathogenesis of ROP. Increasing evidence suggests that perinatal inflammation or infection contributes to ROP pathogenesis. Cytokines and chemokines with a fundamental role in inflammatory responses and that significantly contributing to angiogenesis are analyzed. Microglia cells, the retinal-resident macrophages, are crucial for retinal homeostasis, however, under sustained pathological stimuli release exaggerated amounts of inflammatory mediators and can promote pathological neovascularization. Current modulation of angiogenic cytokines, such as treatment with antibodies to vascular endothelial growth factor (anti-VEGF), has shown efficacy in the treatment of ocular neovascularization; however, some patients are refractory to anti-VEGF agents, suggesting that other angiogenic or anti-angiogenic cytokines need to be identified. Much evidence suggests that genetic factors contribute to the phenotypic variability of ROP. Several studies have implicated the involvement of candidate genes from different signaling pathways in the development of ROP. However, a genetic component with a major impact on ROP has not yet been discovered. Most studies have limitations and did not replicate results. Future research involving bioinformatics, genomics, and proteomics may contribute to finding more genes associated with ROP and may allow discovering better solutions in the management and treatment of ROP.

Estado nutricional al nacer y ganancia de peso postnatal como factores predictores de desarrollo de retinopatía en el prematuro

Introducción: La retinopatía del prematuro (ROP) es la detención del desarrollo neuronal y vascular normal de la retina en el recién nacido pre-término con mecanismos compensatorios, en última instancia patológicos, que resultan en la vascularización aberrante de la retina. La ROP constituye la causa principal de ceguera prevenible en el paciente pediátrico. Múltiples factores de riesgo se han asociado a su desarrollo dentro de los cuales la oxigenoterapia y ganancia de peso postnatal insuficiente son los mayormente relacionados. Se estima que el 15% de casos de compromiso visual severo en el infante en países desarrollados y más del 60% en países en vías de desarrollo son secundarios a esta patología.  Objetivo: Correlacionar el estado nutricional del recién nacido y la ganancia de peso post natal con el desarrollo de retinopatía de la prematurez. Métodos: Se recolectaron datos de 50 pacientes prematuros (<37 semanas de edad gestacional) con desarrollo de retinopatía y bajo peso al nacer (<2,000 gramos).   Se analizó su ganancia de peso postnatal y se comparó con la ganancia de peso postnatal del grupo control, constituido por pacientes prematuros con bajo peso al nacer que no desarrollaron ningún grado de afección visual. Resultados: De los pacientes que no desarrollaron retinopatía se determinó una media de peso al nacer de 1,409 gramos, con un mínimo de 700 gramos y un máximo de 1984 gramos. Los pacientes que desarrollaron retinopatía presentaron una media de 1312 gramos con un mínimo de 650 y un máximo de 1984. De la ganancia de peso postnatal promedio diaria en gramos/día en un período de 4 a 6 semanas, se evaluó que los pacientes sin ROP presentaron una media de 16 gramos/día con un mínimo de 2.86 gramos/día y un máximo de 40 gramos/día; por el contrario, los pacientes con desarrollo de ROP obtuvieron una media de ganancia de peso diaria de 9 gramos/día, con un mínimo de -2.38 gramos/día y un máximo de 35 gramos/día. Conclusión: El peso al nacer no es de significancia estadística para el desarrollo de retinopatía sin embargo, la ganancia de peso postnatal insuficiente sí está relacionada con el desarrollo y progresión de ROP en el prematuro.

Retinal structural changes in preterm children without retinopathy of prematurity

PURPOSE

The aim of this study was to compare all retinal layers' thickness in full-term and preterm children without retinopathy of prematurity (ROP).

METHODS

Cross-sectional study including two groups of patients: group 1 children with history of preterm gestation without ROP (gestational age < 37 weeks) and group 2 healthy children with history of full-term gestation. All subjects underwent an ophthalmic examination including spectral domain-optical coherence tomography. After automatic retinal segmentation, each retinal layer thickness (eight separate layers and overall thickness) was calculated in all nine Early Treatment Diabetic Retinopathy Study areas. Demographic, systemic, gestational, and birth data were collected. Generalized additive regression models were used to analyze the data.

RESULTS

Fifty-one children (51 eyes) were recruited, 19 full-term and 32 preterm children, mean age at ophthalmic examination of 10.58 (4.21) and 14.13 (3.16), respectively. In multivariable analysis, the preterm group's retinal thickness was significantly decreased in total retina nasal outer sector, ganglion cell layer (GCL), and inner plexiform layer (IPL), specifically GCL temporal outer (p = 0.010), GCL superior outer (p = 0.009), IPL temporal outer (p = 0.022), and IPL superior outer (p = 0.004), when compared with full-term group. From the variables compared only with birth head circumference that influenced the models, a non-linear association was identified and consequently modeled with splines through a generalized additive model.

CONCLUSION

This study suggests that preterm children without ROP have structural retinal alterations, mostly in GCL and IPL in outer areas of the macula. Therefore, it is crucial to question gestational history since these retinal changes may be found later in life leading to useless investigation.

Targeted Blood Metabolomic Study on Retinopathy of Prematurity

Purpose

This study aims at exploring alterations of major metabolites and metabolic pathways in retinopathy of prematurity (ROP) infants and identifying biomarkers that may merit early diagnosis of ROP.

Methods

We analyzed targeted metabolites from 81 premature infants (<34 weeks of gestational age), including 40 ROP cases (15 males and 25 females, birth weight 1.263 ± 0. 345 kg, gestational age 31.20 ± 4.62 weeks) and 41 cases (30 males, 11 females, birth weight 1.220 ± 0.293 kg, gestational age 30.96 ± 4.17 weeks) of well-matched non-ROP controls. Metabolites were measured by ultra-performance liquid chromatography-tandem mass spectrometry. Standard multivariate and univariate analysis was performed to interpret metabolomic results.

Results

Glycine, glutamate, leucine, serine, piperidine, valine, tryptophan, citrulline, malonyl carnitine (C3DC), and homocysteine were identified as the top discriminant metabolites. In particular, discriminant concentrations of C3DC and glycine were also confirmed by univariate analysis as statistically significant different between ROP and non-ROP infants.

Conclusions

This study gained an insight into the metabolomic aspects of ROP development. We suggest that higher blood levels of C3DC and glycine can be promising biomarkers to predict the occurrence, but not the severity of ROP.

A Review of Bioactive Factors in Human Breastmilk: A Focus on Prematurity

Preterm birth is an increasing worldwide problem. Prematurity is the second most common cause of death in children under 5 years of age. It is associated with a higher risk of several pathologies in the perinatal period and adulthood. Maternal milk, a complex fluid with several bioactive factors, is the best option for the newborn. Its dynamic composition is influenced by diverse factors such as maternal age, lactation period, and health status. The aim of the present review is to summarize the current knowledge regarding some bioactive factors present in breastmilk, namely antioxidants, growth factors, adipokines, and cytokines, paying specific attention to prematurity. The revised literature reveals that the highest levels of these bioactive factors are found in the colostrum and they decrease along the lactation period; bioactive factors are found in higher levels in preterm as compared to full-term milk, they are lacking in formula milk, and decreased in donated milk. However, there are still some gaps and inconclusive data, and further research in this field is needed. Given the fact that many preterm mothers are unable to complete breastfeeding, new information could be important to develop infant supplements that best match preterm human milk.